Diseases affecting the oral cavity and the teeth and their supporting tissue are very common in adult humans. Such diseases can have a large impact on the individuals affected as they may cause pain, problems with chewing, tooth loss, bad breath etc. and even affect the whole body due to inflammations causing systemic immune responses.
Periodontal disease is an oral disease affecting almost all adults. It is a progressive disease having the serious consequence of leading to partial or complete tooth loss. Periodontal diseases affect the tissues that support and anchor the teeth. The tissues affected by periodontal disease are the gums (including the gingival) periodontal ligament, cementum, and alveolar bone. If not treated, periodontal disease results in the destruction of the gums, alveolar bone, and the outer layer of the tooth root. The main area involved in periodontal disease is the gingival sulcus, a pocket between the teeth and the gums.
Periodontal disease may occur in different forms: gingivitis, acute necrotizing ulcerative gingivitis, adult periodontitis, and localized juvenile periodontitis.
Gingivitis is an inflammation of the outermost soft tissue of the gums which become red and inflamed, loose their normal shape, and becomes prone to bleeding.
Periodontitis is a condition in which gingivitis has extended down around the tooth and into the supporting bone structure. Anaerobic bacteria may grow in pockets between the gums and teeth formed by the accumulation of plaque and tarter. When the bacteria reach the roots of the teeth, the bacteria further cause damage to the tooth supporting bone structure.
Adult periodontitis is the most serious form of the periodontal diseases. It involves the gingiva, periodontal ligament, and alveolar bone, resulting in deep periodontal pockets forming between the teeth, the cementum, and the gums. Plaque, calculus, and debris from food and other sources collect in the pocket. If left untreated, the periodontal ligament can be destroyed and resorption of the alveolar bone may occur allowing the teeth to move more freely and eventually be lost.
The risk of being afflicted by periodontal disease increases with age and bad oral hygiene. The presence of certain species of bacteria in large enough numbers in the gingival pocket and related areas correlates with the development of periodontal disease; removal of these bacteria correlates with reduction or elimination of disease.
Periodontal disease can usually be prevented by good dental hygiene, such as by tooth brushing and flossing. However, once tartar is formed, it has to be removed by a dentist. Also, treatment of periodontitis requires professional dental care. The pockets around the teeth must be cleaned, and all tartar and plaque removed, all the way down to the root if this is also afflicted. Conventional treatment involves both surgical and non-surgical procedures. Surgery may in particular be necessary where the pockets are very deep. Also, antibiotic treatment to remove infectious bacteria may be necessary.
Normally, treatment starts by scraping (scaling and root planing) the tooth surfaces in order to remove both visible bacterial deposits and dental calculus and deposits hidden below the gingival margin. This reduces gingival swelling caused by inflammation and often reduces the depth of the periodontal pockets. However, adequate scaling and root planing performed below the gingival margin is difficult and in deeper periodontal pockets inaccessible infected sites will serve as reservoirs for reinfection. Consequently, surgical procedures, which will enhance access and visibility, may have to be used to completely eliminate soft and hard bacterial deposits. During periodontal surgery, the periodontitis-affected roots are exposed by detaching the gingiva from the roots and alveolar bone. The roots are then freed from bacterial deposits and dental calculus by scaling and root planing. This involves also removal of granulation tissue and root cementum contaminated by bacterial toxins. After the area has been cleaned, the gingival flaps are repositioned and sutured.
Such conventional treatment procedures are conservative and will only, at best, preserve the remaining tooth supporting tissues. Thus, tooth support that has already been lost cannot be recreated by conventional treatment.
Periodontal healing is a primary concern in the treatment of periodontal disease. This is a process largely dependent on the tissue reactions taking place at the hard/soft tissue interface on the root surface. Long-term studies on healing of periodontal wounds with marginal communication following periodontal treatment have indicated that cellular colonization of the wounded area results from a competition between alveolar bone, oral epithelium and mucosal connective tissue as well as periodontal connective tissue.
Most often deep furcation involvements do not lend themselves to successful periodontal healing with conventional periodontal surgery.
Etching during periodontal surgery is performed mainly with three aims: removal of bacterial toxins, removal of smear layer and exposure of collagenous fibres in the root surface and increase visibility through hemostatic effects.
Of these, the two first have been evaluated in vitro employing mainly citric acid and to some extent ortho-phosphoric acid both of which operate at a pH of around 1 (Lowenguth R A, Blieden T M. Periodontal regeneration: root surface demineralization. Periodontology 2000 1993; 1:54).
Scaling and root planing is performed to remove bacterial deposits, calculus and the superficial layers of the root surface (cementum and dentin), structures and tissues which harbor bacterial toxins. Such toxins are not only confined to the bacterial deposits but are also found adsorbed to periodontally diseased root surfaces.
These substances have been shown to inhibit cell attachment in vitro, a function necessary for healing. Thus, the aim of scaling and root planing is to provide a biologically acceptable surface for marginal healing. However, following root surface instrumentation, areas of contaminated cementum, as well as a smear layer covering the instrumented surfaces may still remain. Additional root surface treatment, such as etching has been reported to remove the smear layer.
Application of etching agents has been reported to remove smear and debris which may result from scaling and root planing. However, it also affects the mineralized root surface, although contradictory results have been reported depending on mode of application of the agent.
Burnishing the root surface with a cotton pellet soaked in citric acid appears to expose more intertubular fibrils and widen dentinal tubules to a greater extent compared to simple application of a drop of the acid or by placing an acid-saturated cotton pellet on the root surface without rubbing, although reports have also indicated no difference.
Several studies have studied periodontal healing following citric or ortho-phosphoric acid etching of root surfaces exposed during periodontal surgery, while only few studies have evaluated surrounding soft tissue reactions after acid application. A surprisingly small area of the soft tissue around the site of application appears to suffer any damage despite the low pH (around 1). However, more profound effects on periodontal healing have been reported, although the results appear highly variable.
Since its inception citric and ortho-phosphoric acid etching (pH 1) of root surfaces have been reported to result in new attachment or reattachment. Later these claims have been disputed, and most in vivo studies indicate that connective tissue healing with some reparative cementum formation will result rather than formation of a long epithelial junction. There is also reason to believe that application of citric or ortho-phosphoric acid to a periodontal wound during surgery will increase visibility through hemostatic effects as well as facilitate removal of granulation tissue.
WO96/09029 discloses a composition comprising EDTA for use for conditioning of a biological mineralized surface. The amount of EDTA of the composition of WO96/09029 is near or at saturation of the EDTA when in an aqueous matrix, the saturation point for EDTA lying between 22 and 27% by weight based on the water content of the composition. The pH of the composition is from 6 to 8, preferably around neutral pH of 7. This composition was demonstrated to selectively remove hydroxyapatite but not the collagenous matrix of dentin, in contrast to ortho-phosphoric acid-based etching compositions.
Restorative materials are widely used in the medical field. In the dental area, restorative materials such as amalgam or resin composites are often used to repair dental tissues and bones, for example in the case of dental caries or restoration of tooth injuries. However, in order for such materials to be able to firmly attach to the tooth, the surface of the tooth has to be clean and without adhering bacteria, calculus etc. Also in the case of root fillings, the tooth root canal has to be cleaned and the pulp removed therefrom.
Dental implants are utilized in dental restoration procedures in patients having lost one or more of their teeth. A dental implant comprises a dental fixture, which is utilized as an artificial tooth root replacement. Thus, the dental fixture serves as a root for a new tooth. The dental fixture is typically a screw, i.e. it has the shape of a screw, and it is typically made of titanium, a titanium alloy, zirconium or a zirconium alloy. The screw is surgically implanted into the jawbone, whereafter the bone tissue grows around the screw and the screw is fixated in the bone with the bone in close contact with the implant surface. This process is called osseointegration, because osteoblasts grow on and into the surface of the implanted screw. By means of the osseointegration, a rigid installation of the screw is obtained.
Once the implant screw is firmly anchored in the jawbone, it may be elongated by attachment of an abutment to the screw. The abutment may, just as the screw, be made of titanium, a titanium alloy, zirconium or a zirconium alloy. The shape and size of the utilized abutment are adjusted such that it precisely reaches up through the mucosa after attachment to the screw. A dental restoration such as a crown, bridge or denture may then be attached to the abutment.
Alternatively, the implant screw has such a shape and size that it reaches up through the mucosa after implantation, whereby no abutment is needed and a dental restoration such as a crown, bridge or denture may be attached directly to the screw.
The surface of dental implants sometimes has to be cleaned after placing. This is particularly important when an infection or contamination occurs, causing a progressive degenerative process in the bone adjacent to the implant known as periimplantitis. This is an inflammatory condition of the mucosa and/or bone around the implant which may result in bone loss and eventual loss of the implant. Currently there is no universal agreement on the best treatment for peri-implantitis. However, in periimplantitis it is important to clean the surface of the ailing implant from microbes and contaminants to stop the progression of the disease and ensure re-integration of the implant. Failure to clean the implant surface will eventually lead to loss of bone and implant, and make further alternative treatments difficult and sometimes even impossible. This cleaning may involve mechanical as well as chemical treatment of the implant and the surrounding bone and tissue.
In conclusion, it is important in many aspects to be able to efficiently clean the surface of a mineralized tissue or an implant. Also, there is a need for a composition allowing the cleaning of an implant surface in order to enhance and/or enable osseointegration of the implant. Also, there is a need for a conditioning composition allowing for the treatment of periimplantitis. Thus there is still a need in the field for efficient compositions allowing for a sufficient conditioning of the surface of a mineralized tissue or a medical implant in order to prevent and/or treat diseases affecting the oral cavity, such as periodontal disease and periimplantitis.